JP 2007-144131A (Reference 1) discloses a vehicle seat operating device that is applied to a vehicle seat reclining apparatus. In other words, as shown in FIG. 32, a switching cam (not shown) is disposed in a disk-shaped locking mechanism 200 that selectively switches between states allowing and regulating a tilt of a seat back with respect to a seat cushion, and a biasing member 201 that pivot-biases the cam onto a side of switching to the regulated state is disposed therein as well. Also, a stepped and substantially columnar hinge shaft 205 is inserted into the locking mechanism 200, and a substantially arcuate operation member 206 is connected to the hinge shaft 205 in such a manner as to be integrally pivoted. The cam is inserted in such a manner that the hinge shaft 205 is integrally pivoted, and is pivoted to a side of switching to the allowed state by an operation of the operation member 206 and against a biasing force of the biasing member 201.
Also suggested is, for example, that a second operation member (not shown) is disposed in addition to the operation member 206 in an upper portion of the seat back and is linked to the hinge shaft 205 which constitutes an output side member and the hinge shaft 205 ( cam) is pivoted to the side of switching to the allowed state by an operation of the second operation member as an input side member and against the biasing force of the biasing member 201. Also performed is that a maximum operation amount of the second operation member is allowed to be larger than a maximum operation amount of the operation member 206 for utilization in an operation other than a usual operation for angular adjustment of the seat back with respect to the locking mechanism 200, an example of which includes an operation that allows a change (hereinafter referred to as a “forward tilt”) from a seated state to a forward tilt state.
A pivot amount (movement amount) of the above-described hinge shaft 205 (output side member) is increased at a constant rate of change in response to an increase in the operation amount of the second operation member (input side member). However, a pivoting speed (movement speed) of the cam is different from an optimum movement speed during an operation continuing until the switching to the allowed state and a following operation, and thus optimization thereof is required.